Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, and the description reinforces this with a concrete behavioral claim: the tool "opens nothing by itself," so the agent knows no live Mews session is touched. It also discloses the return shape at a high level (step-by-step screens, buttons, fields). It does not describe response size, formatting, or failure modes, so it adds context without being rich.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The opening sentence and the browser-tool handoff are front-loaded and earn their place. The closing sentence about Mews's Connector API and the absence of an official MCP server adds background but no actionable guidance for invoking this tool, which dilutes an otherwise tight definition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no input parameters, no output schema, and annotations covering the safety profile, the description covers the remaining gaps: what is returned, that nothing is opened, and which tool family performs the actual actions. Only the lack of sibling differentiation keeps it from being complete for tool selection.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters and schema coverage is 100%, so there is no parameter meaning the description needs to supply; the baseline for a 0-param tool applies. No misleading param hints are given.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The first sentence names a specific verb and resource ("List departures in the user's own Mews account") and scopes it to the user's own account. It then explicitly corrects the natural reading of the name by stating it "Returns how to do it in Mews step by step (screens, buttons, fields)" rather than the departure data itself, which is essential disambiguation. It falls short of a 5 because it never contrasts itself with the nearest sibling, mews_list_arrivals.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives a clear activation path: call this to get the procedure, then execute it "with the cotlet_browser_* tools in the user's Mews Cloud Browser." It also sets a negative boundary ("opens nothing by itself"). What is missing is any statement of when to choose this over sibling Mews tools such as mews_list_arrivals or mews_search_reservations.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.